这篇文章主要介绍“android调用JNI SO动态库的方法是什么”,在日常操作中,相信很多人在android调用JNI SO动态库的方法是什么问题上存在疑惑,小编查阅了各式资料,整理出简单好用的操作方法,希望对大家解答”android调用JNI SO动态库的方法是什么”的疑惑有所帮助!接下来,请跟着小编一起来学习吧!
一、静态主要就是将c(.c)或者c++(cpp)的源文件直接加到项目中进行调用,然后在CMakeLists.txt中进行配置。
二、动态调用
1、动态调用使用已经编译好的动态库.so文件
2、android调用ndk类
生成后的so文件
public class SerialPort { p */ public static native int GetSOVer(String ar); static { System.loadLibrary("serialport");//初始化so库(注意这里添加是需要去掉lib与.so) } }
3、.c文件添加
/* * Copyright 2009-2011 Cedric Priscal * * Licensed under the Apache License, Version 2.0 (the "License"); * you may not use this file except in compliance with the License. * You may obtain a copy of the License at * * http://www.apache.org/licenses/LICENSE-2.0 * * Unless required by applicable law or agreed to in writing, software * distributed under the License is distributed on an "AS IS" BASIS, * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. * See the License for the specific language governing permissions and * limitations under the License. */ #include <jni.h> #include <termios.h> #include <unistd.h> #include <sys/types.h> #include <sys/stat.h> #include <fcntl.h> #include <string.h> #include "M1900_drv.h" #include "SerialPort.h" #include "include/tinyalsa/audio_i2s.h" #include "include/tinyalsa/asoundlib.h" #include "android/log.h" #include "newland_linux_so.h" static const char *TAG = "serial_port"; #define LOGI(fmt, args...) __android_log_print(ANDROID_LOG_INFO, TAG, fmt, ##args) #define LOGD(fmt, args...) __android_log_print(ANDROID_LOG_DEBUG, TAG, fmt, ##args) #define LOGE(fmt, args...) __android_log_print(ANDROID_LOG_ERROR, TAG, fmt, ##args) //测试 Java_(固定)_com_littt_util_SerialPort(android包名原来的.更改为_,string ar 传入的字符串参数,JNIEnv *env, jclass固定写法) JNIEXPORT jint JNICALL Java_com_littt_util_SerialPort_GetSOVer(JNIEnv *env, jclass clazz, jstring ar) { // TODO: implement GetSOVer() return 9;//返回一个9的值 }
4、.h头文件中声明
/* DO NOT EDIT THIS FILE - it is machine generated */ #include <jni.h> /* Header for class android_serialport_api_SerialPort */ #ifndef _Included_android_serialport_api_SerialPort #define _Included_android_serialport_api_SerialPort #ifdef __cplusplus extern "C" { #endif JNIEXPORT jint JNICALL Java_com_littt_util_SerialPort_GetSOVer(JNIEnv *env, jclass clazz,jstring v); #ifdef __cplusplus } #endif #endif
5、头文件与c文件写好了,就需要在CMake 中添加.c与.h都需要添加
# For more information about using CMake with Android Studio, read the # documentation: https://d.android.com/studio/projects/add-native-code.html # Sets the minimum version of CMake required to build the native library. cmake_minimum_required(VERSION 3.4.1) # Creates and names a library, sets it as either STATIC # or SHARED, and provides the relative paths to its source code. # You can define multiple libraries, and CMake builds them for you. # Gradle automatically packages shared libraries with your APK. add_library( # Sets the name of the library. serialport # Sets the library as a shared library. SHARED # Provides a relative path to your source file(s). M1900_drv.c M1900_drv.h audio_i2s.c linux_so.cpp mixer.c include/tinyalsa/asoundlib.h include/tinyalsa/audio_i2s.h ) # Searches for a specified prebuilt library and stores the path as a # variable. Because CMake includes system libraries in the search path by # default, you only need to specify the name of the public NDK library # you want to add. CMake verifies that the library exists before # completing its build. find_library( # Sets the name of the path variable. log-lib # Specifies the name of the NDK library that # you want CMake to locate. log) # Specifies libraries CMake should link to your target library. You # can link multiple libraries, such as libraries you define in this # build script, prebuilt third-party libraries, or system libraries. target_link_libraries( # Specifies the target library. serialport # Links the target library to the log library # included in the NDK. ${log-lib}) set(CMAKE_C_FLAGS_RELEASE "${CMAKE_C_FLAGS_RELEASE} -s") set(CMAKE_CXX_FLAGS_RELEASE "${CMAKE_CXX_FLAGS_RELEASE} -s")
6、在build.gradle同样需要配置
plugins { id 'com.android.application' } android { compileSdkVersion 28 buildToolsVersion "28.0.3" defaultConfig { applicationId "com.littt.interphone" minSdkVersion 17 targetSdkVersion 28 versionCode 1 versionName "1.0" testInstrumentationRunner "androidx.test.runner.AndroidJUnitRunner" // cmake externalNativeBuild { cmake { cppFlags "" abiFilters 'armeabi-v7a', 'arm64-v8a', 'x86', 'x86_64' } } } externalNativeBuild { cmake { path "src/main/cpp/CMakeLists.txt" version "3.10.2" } } buildTypes { release { minifyEnabled false proguardFiles getDefaultProguardFile('proguard-android-optimize.txt'), 'proguard-rules.pro' } } sourceSets { main { jniLibs.srcDirs = ['libs'] } } compileOptions { sourceCompatibility JavaVersion.VERSION_1_8 targetCompatibility JavaVersion.VERSION_1_8 } ndkVersion '22.1.7171670' } dependencies { // implementation 'androidx.appcompat:appcompat:1.2.0' // implementation 'com.google.android.material:material:1.2.1' }
7、如果静态调用可以成功,那么就可以生成动态so库文件
点击图中锤子会进行编译。
红框中生成后 so文件
7.1、生成的.so文件(工程文件夹模式)目录为app/build/intermediates/ndk/lib,将其复制到另一个工程的app/lib目录下。
7.2、要使用上述的.so文件 ,必须将工程的包名改为生成.so文件时的包名,要不然 编译能通过,但是app不能正常运行。logcat会提示找不到所调用函数的实现。
7.3、将so文件复制到需要的路径下。
7.4、在gradle.properties中最后加一行:android.useDeprecatedNdk=true。
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